JPH09214245A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a space diversity by avoiding the generation of a difference from a radiation pattern and a direction of a polarized wave vector between two polarized waves in the duplex polarized wave antenna. SOLUTION: The duplex polarized wave antenna has at least one radiation element 2 and a ground plane 4, in which at least side walls 5, 6 are partially provided, and at least one polarized wave selection element 8 (9) is provided between the radiation element 2 and the side walls 5, 6 to send one of polarized waves and to decide a radiation pattern of the other polarized wave.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates generally to antennas, and more particularly to dual polarized antennas for use in cellular base stations.

[0002]

Vertically polarized antennas are used in traditional cellular base stations. Frequently, these antennas have a wide antenna beam, for example at a 120 ° azimuth. To improve the performance of the base station, the two antennas can be mounted at a sufficient distance from each other to allow space diversity.

Alternatively, the use of polarization diversity can achieve a similar improvement in performance. Two different, eg mutually orthogonal, polarizations from one and the same antenna may be used as diversity channels.

In an antenna to be used in connection with polarization diversity, the two polarizations have the same antenna pattern and each polarization vector maintains its orientation for all azimuth angles. This is very important.

In a vertically straight antenna array for fan coverage, the radiating elements can be of different types, eg microstrip patch elements or dipoles. Also, a ground plane can be included in the antenna array.

One purpose of this ground plane is to create the desired radiation pattern. The ground plane is at least partially surrounded by the sidewalls to obtain the desired beam width. These sidewalls, at the same time, mechanically strengthen the antenna structure and hold the internal parts of the antenna in place.

However, due to the electromagnetic properties of the sidewall edges, the vertical and horizontal polarizations are affected differently. The beam width of the vertically polarized signal is different from the beam width of the horizontally polarized signal when the side walls are along the sides of the one or more radiating elements.

This edge effect causes a difference between the two polarizations in both the beam pattern and the polarization vector direction when another combination of the two polarizations is used to obtain polarization diversity. become. For example, +/-
The effect on the 45 ° polarization direction is typically a rotation of the polarization vector rather than a beamwidth difference.

[0009]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a dual polarization antenna which does not create a difference in radiation pattern and / or polarization vector direction between the two polarizations.

[0010]

[Means for Solving the Problems]
This is achieved by an antenna according to the invention, which is equipped with at least one polarization-selecting element which emits one and determines the radiation pattern of the other polarization.

This allows both radiation patterns in a dual polarized antenna to be controlled by appropriate selection of the design and placement of the polarization selective elements.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in more detail with reference to the accompanying drawings. FIG. 1 schematically illustrates an embodiment of a dual polarization antenna 1 according to the principles of the present invention.

The illustrated antenna 1 comprises a diagrammatically illustrated dual polarization radiating element 2 in the form of, for example, a microstrip patch element. Although only one radiating element is shown, it should be understood that the antenna 1 may be provided with multiple radiating elements.

In the illustrated embodiment, the radiating element 2 is supported on a plate 3 of insulating material.

The plate 3 with the radiating element 2 is then supported in a manner not shown by a somewhat larger plate 4. This plate 4 constitutes the ground plane of the antenna 1 and may be made of an insulating material provided with a layer of conductive material. As is apparent from FIG. 1, the plate 3 may be supported from the plate 4, ie at a distance from the ground plane.

In the illustrated embodiment, the plate or ground plane 4 is received in a groove (not shown) in the U-shaped side walls 5 and 6 having a flat bottom 7. Bottom 7 and sidewall 5
The U-shaped contour portion including and 6 is made of a conductive material.

2 of the radiating element 2 in the beam pattern and polarization vector direction, such as occurs at the edges of the side walls 5 and 6.
In order to eliminate the difference between the two polarizations, the antenna 1 is provided according to the invention with at least one polarization selection element.

Each polarization selection element made of a conductive material is
It emits one of the polarizations from the radiating element 2 and acts as a side wall for the other polarization, i.e. determining the radiation pattern.

In the illustrated embodiment, two polarization selection elements are provided. The illustrated polarization selecting elements are fence-like structures 8 and 9 arranged on the ground plane 4. These fence-like structures 8 and 9 respectively extend parallel to the respective side walls 5 and 6 of the U-shaped profile on each side of the radiating element.

As shown, each fence-like structure 8 and 9 of this embodiment includes a top bar 10 interconnected with a bottom bar 11 by a number of cross bars 12. Contains.

The spacing between the crossbars 12 must be chosen to be less than 0.1λ, where λ is the wavelength of the antenna 1.

In the illustrated embodiment in which the fence-like structures 8 and 9 extend parallel to the respective side walls 5 and 6, the antenna pattern for one polarization is mainly the fence-like structures 8 and 9 and the antenna pattern for the other polarizations is mainly determined by the position and height of the side walls 2 and 3.

Thus, the fence-like structures 8 and 9 allow the two antenna patterns to be controlled independently of each other.

In the illustrated embodiment, the bottom 7 of the U-shaped profile, the insulating plate 3 and the ground plane 4 are all at right angles to the side walls 5 and 6 and the fence-like structures 8 and 9 extending along the long sides. Has become.

However, the ground plane 4 and the insulating plate 3 and any structure supporting these elements may be (square) rectangular or even circular. In the latter case, there would be only one side wall (not shown) and only one fence-like structure extending parallel to that single side wall.

According to another non-illustrated embodiment of the antenna according to the invention, each fence-like structure is tilted with respect to its respective side wall. The fence-like structures may be tilted toward or away from their respective sidewalls.

If the fence-like structures are tilted towards the respective side walls, the tops of the respective fence-like structures may be brought into contact with the tops of the respective side walls.

Depending on the application of the antenna, the fence-like structure may extend along the entire length of the side wall or along a part thereof.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an embodiment of an antenna according to the present invention.

[Explanation of symbols]

 2 Radiating element 4 Ground plane 5 Side wall 6 Side wall 8 Polarization selection element 9 Polarization selection element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Lars Torstenson Goetheborg, Sweden, Barnscordsgatan 4 a

Claims (10)

[Claims] 1. A dual polarized antenna comprising at least one radiating element (2) and a ground plane (4) such that the ground plane is at least partially surrounded by sidewalls (5, 6). 2. A dual polarization antenna, comprising: at least one polarization selection element (8, 9) for transmitting one polarization and determining a radiation pattern of the other polarization. 2. The dual polarization antenna as claimed in claim 1, wherein the at least one polarization selection element (8, 9) comprises the radiating element (2) and at least part of the side walls (5, 6). A dual polarization antenna characterized in that it is provided between the two. 3. A dual polarization antenna as claimed in claim 2, characterized in that the at least one polarization selection element (8, 9) extends parallel to the side walls (5, 6). Dual polarized antenna. 4. The dual polarization antenna according to claim 2, wherein the at least one polarization selection element is tilted with respect to the side wall. 5. The dual polarization antenna according to claim 4, wherein the at least one polarization selection element is inclined toward the side wall. 6. The dual polarization antenna according to claim 5, wherein the top of the at least one polarization selection element is in contact with the top of the side wall. antenna. 7. The dual polarization antenna according to any one of claims 2 to 6, wherein the at least one polarization selection element (8, 9) is located on the side wall (5, 6). A dual polarization antenna characterized in that it extends along the entire length. 8. The dual polarization antenna according to any one of claims 1 to 7, wherein the at least one polarization selection element (8, 9) is a fence-shaped structure. Characteristic dual polarization antenna. 9. The dual polarized antenna according to claim 8, wherein the fence-like structure comprises a top bar (10) interconnected with a bottom bar (11) by a cross bar (12). A dual polarization antenna. 10. The dual polarization antenna according to any one of claims 1 to 9, wherein the ground plane (4).
Has side walls (5, 6) along its long sides perpendicular to it, characterized in that the polarization-selecting element (8, 9) consists of the radiating element (2) and each side wall (5, 6). A dual polarization antenna that is installed between them.